There are economies of scale on the Great Lakes/St. Lawrence Seaway system, even with the present short navigation system. Greater economies could be realised by developing vessels capable of both lake and ocean voyage.
Topic: 2.3 Inland Waterways
American inland waterway transport is subject to a complicated system of control by government agencies, which require knowledge of costs. Inland waterway costs have fallen slightly, and a large share of the market has come into the hands of a small number of firms. The authors find increasing returns to scale for size of firm and output.